@janbb Really! I had no idea they were lyrics from a folksong! I suppose I can find it without too much laborious computer-fiddling; can you tell me the title, more about it?
I “thru-hiked” the Appalachian Trail, from Georgia to Maine, years ago…there are “trail registers,” logbook sort of things in the lean-to shelters along the trail; and some hiker ahead of me (I never met him/her) would repeatedly make that entry. In view of the fact that most of the wooden shelters were full of mice, it was quite apropos, meaningful to hikers that would spend the night in them. I rarely slept in shelters—had an adequate tent, preferred more solitude—but whenever I did, there were the mousies, skittering about in the dark, literally inches away, making one feel a bit uncomfortable, hence the little poem was so meaningful, relevant, enjoyable in a sadistic sort of way, to those who read it. But alas, “Revenge is mine, sayeth the Lord.”